This invention relates to a method of packaging perishable foods. More particularly, this invention relates to a method of packaging perishable foods suitable to keep them fresh without suffering injury on their surface during storage or transportation.
In the case of perishable foods such as fruits, vegetables, root-crops and eggs, commercial values are largely influenced by freshness and extent of injury. As the places where these foods are produced are generally far distant from urban areas, long-distance transportation is required for supplying the foods to consumers in urban areas. Therefore, it is a key technical problem in such long-distance transportation of perishable foods to avoid deterioration of freshness and keep the degree of superficial injury as low as possible thereby maintaining the commercial value of such foods.
In the prior art, methods utilizing paper or pulp-mold packages as well as methods utilizing sheets of foamed resins are employed for packaging such perishable foods. In the former methods, however, there are some drawbacks, i.e., poor water resistance makes the foods non-hygienic, low cushioning action results in damaging of the contents after falling or shock, and poor dimensional stability against change in temperatures causes injury of the contents. On the other hand, the latter methods have also some drawbacks, i.e., inferior air-permeability and moisture-permeability fail to maintain freshness of perishable foods, injury is caused on the surface of the packaged products, and the packaging material tends to be damaged. Accordingly, all of these methods are unsatisfactory because of these drawbacks.